Surface acoustic wave sensor device and method of controlling liquid using the same

ABSTRACT

A surface acoustic wave sensor device includes a main body and a liquid controller disposed external to the main body. The main body includes a sample chamber, a surface acoustic wave sensor connected to the sample chamber, a first disposal chamber connected to the surface acoustic wave sensor and channels connecting the sample chamber, the surface acoustic wave sensor and the first disposal chamber. The liquid controller controls flow of a sample through the main body.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No.2009-54394, filed on Jun. 18, 2009, and all the benefits accruingtherefrom under 35 U.S.C. §119, the content of which in its entirety isherein is incorporated by reference.

BACKGROUND

1) Field

The general inventive concept relates to a surface acoustic wave (“SAW”)sensor and, more particularly, to a device including the SAW sensor anda method of controlling a liquid using the same.

2) Description of the Related Art

A surface acoustic wave sensor is a device that senses, e.g., detects, atarget material, such as an analyte, using a surface acoustic wave(“SAW”).

Generally, the SAW sensor is disposed on a substrate made of apiezoelectric material, and includes a receptor that binds to a specificdesired target material on a surface of the SAW sensor. Morespecifically, when a solution containing the target material flows intothe SAW sensor, signals, such as wavelengths, for example, are changedby mechanical, chemical and/or electrical reactions of the targetmaterial with the receptor. As a result, properties and/orcharacteristics of the target material may be determined by monitoringthe changes in the signals.

A SAW sensor device is typically used to analyze and monitor a targetmaterial contained in a sample, such as a chemical liquid sample or abiological liquid sample (such as a body fluid, for example).

The SAW sensor is particularly sensitive to a pressure of a liquid, aswell as to viscosity or density of a medium (such as the liquid), andcorresponding mass changes on a surface of the SAW sensor. Accordingly,precise control of the liquid is desired to minimize noise, which is asignal change due to factors other than the detected mass changes, forexample.

There is typically an abundant amount of target materials in a giventarget sample solution analyzed by the SAW sensor, and the abundanttarget materials cause contamination of valves and pumps, as well aschannels and chambers, for example, in the SAW sensor device, as theliquid flows through the SAW sensor. As a result of the contamination,substantial errors are introduced when the target sample solution isanalyzed.

To reduce and/or effectively prevent these and other errors, disposable,i.e., not reusable, valves and pumps are used. However, using disposablevalves and pumps has disadvantages, which include reducing commercialand economic feasibility and efficiency of the SAW sensor.

SUMMARY

Exemplary embodiments include a surface acoustic wave (“SAW”) sensordevice which provides advantages that include, but are not limited to,substantially increased reliability and accuracy of analyses performedby the SAW sensor by effectively minimizing generation of noise whiledetecting and/or sensing predetermined materials in a liquid sample andperforming quantitative analyses thereof, and a method of controlling aliquid using the same. Exemplary embodiments further provide a SAWsensor device having substantially improved economic and commercialfeasibility and efficiency.

Alternative exemplary embodiments provide a method for moving andcontrolling a liquid by air pressure or ventilation from outside a SAWsensor device.

In an exemplary embodiment, a SAW sensor device includes a main body anda liquid controller disposed external to the main body. The main bodyincludes a sample chamber, a SAW sensor connected to the sample chamber,a first disposal chamber connected to the SAW sensor, and channelsconnecting the sample chamber, the SAW sensor and the first disposalchamber. The liquid controller controls flow of a sample through themain body.

According to an alternative exemplary embodiment, a SAW sensor systemincludes a first SAW sensor device and a second SAW sensor device. Eachof the first SAW sensor device and the second SAW sensor device includesa main body and a liquid controller disposed external to the main body.The liquid controller controls flow of a sample through the main body.The main body includes a sample chamber, a SAW sensor connected to thesample chamber, a first disposal chamber connected to the SAW sensor,and channels connecting the sample chamber, the SAW sensor and the firstdisposal chamber. A receptor is disposed on a surface of the SAW sensorof the first surface acoustic wave sensor device, but a receptor is notdisposed on a surface of the SAW sensor of the second surface acousticwave sensor device.

According to yet another exemplary embodiment, a method of controlling aliquid in a SAW sensor device is provided. The SAW sensor deviceincludes a main body and a liquid controller disposed external to themain body. The main body includes a sample chamber, a SAW sensorconnected to the sample chamber, a first disposal chamber connected tothe SAW sensor, and channels connecting the sample chamber, the SAWsensor and the first disposal chamber. The method includes providing adriving force from the liquid controller, disposed external to the mainbody, to the main body, and moving the liquid from the sample chamber tothe SAW sensor using the driving force.

According to still another exemplary embodiment, a device forcontrolling a liquid includes a SAW sensor. The SAW sensor includes amain body and a liquid controller disposed external to the main body.The liquid controller controls flow of a sample through the main body.The main body includes: a first sample chamber; a second sample chamberconnected to the first chamber; a SAW sensor connected to the firstsample chamber and the second sample chamber; a first disposal chamberconnected to the SAW sensor; and channels connecting the first samplechamber, the second sample chamber, the SAW sensor and the firstdisposal chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages will become morereadily apparent by describing exemplary embodiments in further detailwith reference to the accompanying drawings, in which:

FIG. 1 is an exploded partial cross-sectional view of a an exemplaryembodiment of a surface acoustic wave (“SAW”) sensor device;

FIG. 2( a) is a plan view of a cover of the SAW sensor device of FIG. 1;

FIG. 2( b) is a plan view of a main body of the SAW sensor device ofFIG. 1; and

FIG. 3 is an exploded perspective view of the SAW sensor device of FIG.1.

DETAILED DESCRIPTION

The invention now will be described more fully hereinafter withreference to the accompanying drawings, in which various embodiments areshown. This invention may, however, be embodied in many different forms,and should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like reference numerals refer tolike elements throughout.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be present therebetween. In contrast, when an element isreferred to as being “directly on” another element, there are nointervening elements present. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of the present invention.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises” and/or “comprising,” or“includes” and/or “including” when used in this specification, specifythe presence of stated features, regions, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, regions, integers, steps,operations, elements, components, and/or groups thereof

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

As will now be described in further detail with reference to theaccompanying drawings, a surface acoustic wave (“SAW”) sensor deviceaccording to an exemplary embodiment includes a main body including asample chamber, a SAW sensor connected to the sample chamber, a disposalchamber connected to the SAW sensor, and which includes a sample passingthrough the SAW sensor, and channels connecting the sample chamber, theSAW sensor and the disposal chamber. In addition, the SAW sensor deviceaccording to an exemplary embodiment includes a liquid controller, whichcontrols flow of a liquid, is disposed outside, e.g., external to, themain body.

In contrast with the exemplary embodiments described herein, aconventional SAW sensor device includes a liquid controller installedinside, e.g., internal to, a main body thereof, in a path or channelbetween a chamber and a SAW sensor, resulting in contamination of theliquid controller by a liquid sample therein, which causes generation ofa substantial amount of noise.

However, according to exemplary embodiments described herein, the liquidcontroller is disposed outside the main body, and thus is not in directcontact with the chamber or the SAW sensor. Accordingly, contaminationof the liquid controller and generation of noise is substantiallyreduced and/or is effectively prevented.

More particularly, the liquid controller in an exemplary embodiment maybe disposed on an upper surface of the main body, e.g., a top surface ofthe main body, as will be described in further detail below. As aresult, a liquid, e.g., a sample, is controlled from an upper portion ofthe sample chamber, and thus contact of the liquid with the liquidcontroller is effectively eliminated without application of externalpower, as will also be described in further detail below.

FIG. 1 is an exploded partial cross-sectional view of an exemplaryembodiment of a SAW sensor device, FIG. 2( a) is a plan view of a coverthereof, FIG. 2( b) is a plan view of a main body thereof and FIG. 3 isan exploded perspective view thereof

Referring to FIGS. 1-3, a SAW sensor device 100 according to anexemplary embodiment includes a main body 200, a cover 300 which coversan upper portion of the main body 200 and a liquid controller 310disposed on the cover 300. The cover may be disposed on an uppersurface, e.g., a top surface (as viewed in FIG. 1), of the main body200. In an exemplary embodiment, the main body 200 includes a firstsample chamber 211 and a second sample chamber 212, each containing asample, such as a liquid, a SAW sensor 400 connected to the first samplechamber 211 and the second sample chamber 212 through a first channel510, connected to both the first sample chamber 211 and the secondsample chamber 212, and a first disposal chamber 220 connected to theSAW sensor 400 through a second channel 520.

The liquid controller 310 controls inflow/outflow of a sample, e.g., aliquid, within the main body 200 and, more particularly, through the SAWsensor 400. Specifically, the liquid controller 310 controls, amongother things, a flow rate of the liquid through the main body 200, aswill be described in greater detail below. In an exemplary embodiment,for example, the liquid controller 310 controls the flow of the liquidby adjusting an inflow and/or an outflow of air through the main body200. To control the flow, exemplary embodiments of the liquid controller310 include, but are not limited to, valves 321, 322, 323 and 324, whichcontrol the inflow/outflow of the liquid, as well as one or more pumps(e.g., a negative pressure pump 330 and/or a positive pressure pump335), which control the flow pressure and/or flow rate of the liquidthrough the main body 200 and, subsequently, through the SAW sensor 400.

More specifically, the valves 321, 322, 323 and 324 control whether asample solution is inputted to a surface of the SAW sensor 400 duringoperation of the SAW sensor device 100. Because the valves 321, 322, 323and 324 control the inflow/outflow of the liquid, the valves 321, 322,323 and 324 are connected to at least the first sample chamber 211 andthe second sample chamber 212, each containing sample solutions.Additionally, the valves 321, 322, 323 and 324 may be connected to thefirst sample chamber 211 and the second sample chamber 212, as well asthe first disposal chamber 220, as will be described in greater detailbelow.

The negative pressure pump 330 and/or the positive pressure pump 335controls the flow of the liquid through the main body 200 including theSAW sensor 400 disposed therein. Specifically, the samples in the firstsample chamber 211 and the second sample chamber 212 move to the firstdisposal chamber 220 through the SAW sensor 400 by a network of channelsbased on a pressure difference from the negative pressure pump 330and/or the positive pressure pump 335 (hereinafter collectively referredto as “pumps”). More specifically, the pumps compress and/or decompressthe first sample chamber 211, the second sample chamber 212 and/or thefirst disposal chamber 220 (hereinafter collectively referred to as“chambers”), thereby providing a driving force to transfer the liquidsamples from the first sample chamber 211 and the second sample chamber212 to the first disposal chamber 220 through the SAW sensor 400.

The pumps compress or decompress the chambers using positive and/ornegative pressures. Therefore, the positive pressure pump 335 isdisposed proximate to and in fluid communication with the first samplechamber 211 and the second sample chamber 212, which have the liquidflowing to the SAW sensor 400. In contrast, the negative pressure pump330 is disposed proximate to and in fluid communication with the firstdisposal chamber 220, which receives the liquid expelled from the SAWsensor 400, as shown in FIG. 1.

Therefore, in an exemplary embodiment, the pump is the negative pressurepump 330, which is disposed at an outflow portion of the SAW sensordevice 100, e.g., at an outlet of the liquid controller 310, as shown inFIG. 1. Thus, when the valve 323, connected to the first disposalchamber 220, is connected to the negative pressure pump 330, pressure issequentially applied to the first disposal chamber 220, the SAW sensor400, the first sample chamber 211 and the second sample chamber 212. Asa result, when air pressure in the first disposal chamber 220 is reducedby ventilating the first sample chamber 211 and the second samplechamber 212 using the negative pressure pump 330, the liquid in thefirst sample chamber 211 and the second sample chamber 212 movesequentially to the SAW sensor 400 and then to the first disposalchamber 220, due to a negative pressure, e.g., a vacuum (relative topressures in the first sample chamber 211 and the second sample chamber212), created in the disposal chamber 220 by the negative pressure pump330.

In an alternative exemplary embodiment, the positive pressure pump 335may be disposed at an inflow portion of the device, e.g., an inlet ofthe liquid controller 310, as also shown in FIG. 1. Accordingly, whenthe valves 321 and 322, connected to the first sample chamber 211 andthe second sample chamber 212, respectively, are connected to thepositive pressure pump 335, the first disposal chamber 220 isventilated, and air is thereby exhausted from the positive pressure pump335 and flows into the first sample chamber 211 and the second samplechamber 212 through the valves 321 and 322, respectively. As a result,the liquid moves to the SAW sensor 400 along channels (described ingreater detail below) due to a positive pressure (relative to a pressurein the SAW sensor and first disposal chamber 220) generated in the firstsample chamber 211 and the second sample chamber 212 by the positivepressure pump 335.

It will be noted that, in alternative exemplary embodiments, either orboth the negative pressure pump 330 and the positive pressure pump 335are included in the SAW sensor device 100.

In an exemplary embodiment, the liquid controller 310 may be directlyor, alternatively, indirectly connected to the main body 200 to controlthe flow of the sample therethrough. For example, as best shown in FIGS.2( a) and 2(b), the valves 321 and 322 are connected to the first samplechamber 211 and the second sample chamber 212, respectively, while thevalves 323 and 324 are connected to the first disposal chamber 220 andthe second disposal chamber 230, respectively. In addition, the valves323 and 321 may be connected to the negative pressure pump 330 (FIG. 1)and the positive pressure pump 335 (FIG. 1), respectively. Thus, theliquid controller 310 according to an exemplary embodiment includes astructure in which the negative pressure pump 330, the valve 323 and thefirst disposal chamber 220 are be sequentially connected, butalternative exemplary embodiments are not limited thereto.

In an exemplary embodiment, to connect the valves 321, 322, 323 and 324(hereinafter collectively referred to as “valves”) and/or the pumps tothe chambers, openings 250, e.g. apertures 250, may be formed in asurface of the first sample chamber 211 and the second sample chamber212, as well as in a surface of the first disposal chamber 220 and thesecond disposal chamber 230. Accordingly, the first sample chamber 211and the second sample chamber 212, as well as the first disposal chamber220 and the second disposal chamber 230, may be connected to the valvesand/or the pumps by channels at corresponding respective portionsthrough the openings 250.

In an exemplary embodiment, for example, the valves may be connectedsubstantially perpendicular to the surfaces of the first sample chamber211 and the second sample chamber 212 and/or the first disposal chamber220 via the openings 250. As a result, a distance and time required toapply the pressure to the chambers is effectively minimized.

As discussed above, the first sample chamber 211, the second samplechamber 212, the first disposal chamber 220 and the second disposalchamber 230 may each include at least one of the openings 250 to allowthe liquid to flow into or out of the each of the chambers. In additionto the openings 250, the first sample chamber 211 and the second samplechamber 212 may also include additional openings 260, e.g., additionalapertures 260, for connection to the SAW sensor 400 and/or to otherchambers, as shown in FIGS. 2( a) and 2(b). The channels may be coupledto the openings 250 and/or the additional openings 260, thereby forminga liquid path through the main body 200.

More specifically, referring to FIGS. 1-3, the openings 250, hereinafterreferred to as “first openings 250,” are formed in the first samplechamber 211, the second sample chamber 212, the first disposal chamber220 and the second disposal chamber 230, while second openings 350(e.g., second apertures 350), positions of which correspond to the firstopenings 250 of the main body 200, are formed in the cover 300 disposedabove the main body 200, as best shown in FIGS. 2( a) and 2(b). Inaddition, the second openings 350 are connected to the valves 321, 322,323 and 324, as shown in FIG. 2( a). However, it will be noted thatalternative exemplary embodiments are not limited to the configurationor components shown in FIGS. 2( a) and 2(b).

As shown in FIG. 1, a sealing member 360, such as an O-ring, may bedisposed at the second opening 350 connecting the cover, including theliquid controller 310 therein/thereon, to the main body 200, tosubstantially increase reliability of control of the sample liquid andto effectively prevent contact between the sample liquid and the liquidcontroller 310.

The liquid controller 310 may be disposed separate from the main body200 and independently disposed on the main body 200, or, alternatively,may be integrated with the main body 200.

The liquid controller 310 may also include a baffle (not shown), such asa plug, obstacle or other device, which changes the liquid flow throughthe liquid controller 310.

Thus, the SAW sensor device according to an exemplary embodimentincludes the first sample chamber 211, the second sample chamber 212 andthe first disposal chamber 220. The first sample chamber 211 and thesecond sample chamber 212 contain a portion of the sample liquid thatdoes not pass through the SAW sensor 400, and the first disposal chamber220 contains a portion of the sample liquid that passes through the SAWsensor 400.

In alternative exemplary embodiments, multiple sample chambers may beprovided, and each may contain a different sample from the other samplechambers. The samples may be liquids, and examples of the liquidsinclude, but are not limited to, a solution containing a target material(hereinafter, referred to as a “target sample”), a secondary reactionsolution, a reference solution and a washing solution. One or moretarget samples may be used.

Examples of the target samples may include, but are not limited to,biological samples, such as saliva, sputum, cerebrospinal fluid, blood,serum, plasma, urine and biopsy materials.

The target sample is a solution including a target material. The targetmaterial is a material to be detected by the SAW sensor 400.

Examples of the target materials may include, but are not limited to,bio molecules such as proteins, antibodies, antigens, deoxyribonucleicacid (“DNA”), ribonucleic acid (“RNA”), viral cells, bacterial cells,animal cells and tissues, and bio products such as toxins generatedtherefrom.

The reference solution is a liquid compared to the target sample forcomparison by signal analysis. The reference solution may have similarcharacteristics, such as viscosity, conductivity and density, to thetarget sample, and may be a buffer solution.

The reference solution may be the same as the washing solution.

Referring again to FIG. 1, side surfaces 240 of the first sample chamber211, the second sample chamber 212 and/or the first disposal chamber 220may be tapered at a slope with respect to an imaginary planesubstantially perpendicular to a plane defined by the upper surface ofthe main body 200 (e.g., may be tapered at an acute angle from they-axis shown in FIG. 3). Because of the slope, a moving distance of theliquid is reduced, and an acceleration force is provided during themoving of the liquid. As a result, unnecessary loss of the liquid isthereby reduced.

In an exemplary embodiment, the acute angle of the slope may be, but isnot limited to, from about 1 degree (°) to about 60° or, alternatively,may be from about 5° to about 30°.

As discussed above, in the SAW sensor device according to an exemplaryembodiment, the chambers and the SAW sensor 400 are in fluidcommunication with each other through the channels.

More specifically, as shown in FIGS. 1-3, the channels include the firstchannels 510, connecting the first sample chamber 211 and the secondsample chamber 212 to the SAW sensor 400, and the second channel 520connecting the SAW sensor 400 to the first disposal chamber 220. It willbe noted that alternative exemplary embodiments are not limited to theforegoing components, and may further include additional channelsconnecting additional chambers and/or components of the SAW sensordevice 100.

The first channels 510 and the second channels 520 disposed in the mainbody 200 to form liquid paths therein. However, the first channels 510and the second channels 520 prevent the liquids from moving whenexternal power is not applied to the SAW sensor device 100 or the SAWsensor device 100 is not in operation.

In an exemplary embodiment, the first channels 510, connecting the firstsample chamber 211 and the second sample chamber 212 to the SAW sensor400, allow the liquid to flow upward from lower portions of the firstsample chamber 211 and the second sample chamber 212 to an upper, e.g.,top, surface of the SAW sensor 400 (as viewed in FIGS. 1 and 3).Accordingly, the liquid in the first sample chamber 211 and the secondsample chamber 212 are effectively prevented from moving through thechannels without external power, thereby easily controlling the flow ofthe liquid during operation, while preventing the liquids from movingwhen external power is not applied to the SAW sensor device 100 or theSAW sensor device 100 is not in operation.

As shown in FIG. 1, the first channel 510 extends upward (e.g., alongthe y-axis, as shown in FIG. 3) toward the upper surface of the mainbody 200, e.g., towards the cover 300 and liquid controller 310, fromthe lower portion of the first sample chamber 211 and the second samplechamber 212 (note that only the first the first sample chamber 211 isvisible in the cross-section shown in FIG. 1). Thereafter, the firstchannel 510 extends substantially perpendicular to a plane defined by alower surface of the first sample chamber 211 and the second samplechamber 212 toward the SAW sensor 400 (e.g., along the x-axis of FIG.3), and then extends downward and substantially perpendicular to theupper surface of the SAW sensor 400.

In an exemplary embodiment, the second channel 520, connecting the SAWsensor 400 to the first disposal chamber 220, allows the liquid to flowupward from and substantially perpendicular to the plane defined by theupper surface of the SAW sensor 400, and then to flow into the firstdisposal chamber 220. Thus, the liquid moving to the first disposalchamber 220 is effectively prevented from flowing backward to the SAWsensor 400.

As shown in FIG. 1, the second channel 520 extends upward from andsubstantially perpendicular to the plane defined by the upper surface ofthe SAW sensor 400 (e.g., along the y-axis of FIG. 3), and is connectedto an upper portion of the first disposal chamber 220, e.g., at a sideof the first disposal chamber 220 facing the SAW sensor 400.Alternatively, the second channel 520 may extend upward from andsubstantially perpendicular to the plane defined by the upper surface ofthe SAW sensor 400, and then be connected to a lower portion of thefirst disposal chamber 220 at the side thereof facing the SAW sensor400. Thus, in an exemplary embodiment, the backward flow of the sampleliquid in the first disposal chamber 220 is effectively prevented fromflowing backward into the SAW sensor 400.

It will be noted that, in alternative exemplary embodiment, thestructures and/or arrangements of the first channels 510 and the secondchannels 520 are not limited to the foregoing description, and anystructure connecting the chamber to the SAW sensor 400 is included inthe scope of the general inventive concept disclosed herein.

I an exemplary embodiment, external channels, configured to connect toan external device, may also be included in the SAW sensor device 100.More specifically, first external channels 540 and second externalchannels 550 may be provided, as shown in FIGS. 1-3. Moreover, the firstexternal channels 540 and second external channels 550, as well as theopenings 250, may be disposed higher along the y-axis than the topsurfaces of the chambers, as also shown in FIGS. 1-3. Accordingly, theexternal pressure provided by the pumps, e.g., the transfer drivingforce of the liquid, may be applied to at a lower portion of thechambers from an upper portion thereof Additionally, the first externalchannels 540 and the second external channels 550 and/or the openings250 may be engaged with the valves, as discussed above, and may thuscontrol opening and closing of the chambers for ventilation when theexternal pressure is introduced by the pumps.

In an exemplary embodiment, a number of the sample chambers and/or thedisposal chambers may be more than one. For example, an alternativeexemplary embodiment may include two or three of each of the samplechambers and the disposal chambers. In addition, an alternativeexemplary embodiment may also include more than one SAW sensor 400. Inthese alternative exemplary embodiments, however, it will be noted thatconnections between the chambers and/or or between the chambers and theSAW sensors is not limited to the foregoing discussion, as long as theabovementioned components can be ventilated as described herein.

As discussed above, the SAW sensor 400 detects characteristics of atarget material, but specific configurations of the SAW sensor 400 arenot particularly limited. In general, the SAW sensor 400 according to anexemplary embodiment includes a pair of inter-digital transducers(“IDTs”), e.g., metal electrodes (not shown), disposed on a substrate410 (FIG. 1) having a piezoelectric characteristic.

More specifically, the piezoelectric material forming the substrate 410is a material having electrical characteristics which are converted,e.g., are altered, when a mechanical signal is applied thereto (e.g.,having a “Piezoelectric effect”), or, alternatively, generating amechanical signal when an electrical signal is applied thereto (e.g., a“reverse” Piezoelectric effect). In an exemplary embodiment, forexample, the piezoelectric material may include lithium niobate(LiNbO₃), lithium tantalite (LiTaO₃), lithium teraborate (Li₂B₄O₇),barium titanate (BaTiO₃), lead zirconate (PbZrO₃), lead titanate(PbTiO₃), Zr-doped lead titanates (PbZr_(x)Ti_(1-x)O₃ or “PZT”), zincoxide (ZnO), gallium arsenide (GaAs), quartz or niobate, but alternativeexemplary embodiments are not limited thereto.

The IDTs (not shown) are an interface between an electrical circuit andan acoustic delay line (not shown), which may include, but is notlimited to, a thin metal film of an aluminum alloy, a copper alloy orgold.

A first IDT of the pair of IDTs generates a surface acoustic wave basedon a signal applied thereto. Accordingly, the first IDT is referred toas an “input IDT” or a “transmitter.” The surface acoustic wavegenerated by the first IDT is delivered to a second IDT of the pair ofIDTs by expansion and compression with a specific frequency along asurface of the substrate, and is converted into an electrical signal dueto the reverse piezoelectric effect in the second. The second IDT isreferred to as an “output IDT” or a “receiver.”

A receptor 405 (FIG. 2), which binds to a target material present in atarget sample, is disposed on a surface of the SAW sensor 400. Thereceptor may be, but is not particularly limited to, a material thatspecifically reacts with the target material.

In an exemplary embodiment, for example, the receptor may includeproteins, antigens, antibodies, enzymes, DNA, RNA, peptide nucleic acids(“PNA,” e.g., artificial DNA), cells or olfactories.

The SAW sensor device 400 may include a plurality of the SAW sensors400, depending on a type or kind of liquids, target materials andreceptors to be analyzed. In addition, the SAW sensor device 100 mayinclude an oscillator 600 (FIG. 1), which generates a signal configuredto induce a SAW, but alternative exemplary embodiments are not limitedthereto.

A method of controlling a sample liquid flow in an exemplary embodimentof the SAW sensor device 100 will now be described in further detail. Itwill be noted that, while an exemplary embodiment including the negativepressure pump 330 will now be described, that alternative exemplaryembodiments are not limited thereto, but may instead include either orboth the negative pressure pump 330 and/or the positive pressure pump,as discussed in greater detail above. Referring to FIGS. 1-3, when thevalve 323 is gated, e.g., is opened, and then the negative pressure pump330 is driven, a negative air pressure, e.g., a vacuum, is formed in thechambers by outflow of air. Accordingly, a pressure gradient isgenerated between the air and the liquid in the chambers, causing theliquid to move. Specifically, the liquid moves from the first samplechamber 211 and the second sample chamber 212 to an inlet port of theSAW sensor 400 through the first channel 510 by gating the valve 323connected to the negative pressure pump 330. As a result, the liquidflows through the SAW sensor 400, and moves to the first disposalchamber 220 through an outlet port of the SAW sensor 400.

Additionally, when the valve 321 of a desired chamber, e.g., the firstsample chamber 211, is gated, the pressure gradient between the air andliquid in the chambers is removed, by the liquid flowing out of thechamber. In contrast, when the valve 321 (and, subsequently, theopenings 250 and 350) are closed, the pressure gradient is not able tobe offset, and the liquid does not flow through the chamber.

Accordingly, in an exemplary embodiment, the liquid flow to desiredportions of the SAW sensor 400 is controlled, even though the liquidcontroller 310, e.g., the valves 321, 322, 323 and 324, is not disposedinternally within the main body 200 of the SAW sensor device 100. As aresult, analysis errors caused by contamination of the target sample aresubstantially reduced and/or are effectively minimized In addition, theliquid controller 310, including the valves 321, 322, 323 and 324 andthe negative pressure pump 330, for example, are re-usable and maytherefore be used for repeated analyses, thereby substantially reducingcosts.

When the liquid flow is controlled by the inflow/outflow of the air,and, more particularly, when the sample liquids flow into the SAW sensor400, air bubbles generated by the air may cause noise, resulting in anundesired change in a signal outputted from the SAW sensor 400.Specifically, when a first liquid is injected into the first samplechamber 211 and is thereafter replaced with a second liquid, noise maybe generated due to air bubbles formed during injection of the firstliquid, so that a reliability and/or accuracy of sensing of the secondliquid is adversely affected.

To prevent this, the SAW sensor device 100 according to an exemplaryembodiment may further include an additional chamber configured tocapture the air bubbles, thereby effectively preventing the noise.

For example, referring again to FIGS. 1-3, to prevent inflow of the airbubbles to the SAW sensor, a second disposal chamber 230 captures theair bubbles. The second disposal chamber 230 may be connected betweenthe first sample chamber 211, the second sample chamber 212 and the SAWsensor 400 via a third channel 530.

Accordingly, after a first liquid moves from the first sample chamber211 to the SAW sensor 400 via the first channel 510, air bubblescontained in the first channel 510 are captured by the second disposalchamber 230 via the third channel 530, and a second liquid maythereafter move to the SAW sensor 400, such as from the second samplechamber 212 via the first channel 510, for example.

Referring to FIGS. 1-3, an operating sequence of an exemplary embodimentof the SAW sensor device 100 including the negative pressure pump 330connected to the valve 323 disposed above the first disposal chamber 220will now be described in further detail.

The valve 323 disposed above the first disposal chamber 220 is gated,e.g., is opened, to form a vacuum in the first disposal chamber 220 andthe first sample chamber 211, thereby increasing a pressure in the firstliquid in the first sample chamber 211, resulting in the first liquidflowing into the SAW sensor 400.

The valve 324 above the second disposal chamber 230 is gated to increasepressure in the second liquid in the second sample chamber 212,resulting in capturing the remaining solution of the first sample andair bubbles in the first channel 510 in the second disposal chamber 230via the third channel 530.

The valve 323 above the first disposal chamber 220 is gated again toincrease pressure in the second liquid in the second sample chamber 212,resulting in injecting the second liquid into the SAW sensor 400.

In an alternative exemplary embodiment, a system for analyzing a targetmaterial in a sample is also provided. More specifically, the systemincludes: a first SAW sensor device 100 (hereinafter referred to as a“test SAW sensor device”) in which a receptor 405 (FIG. 2) which reactswith a target material is disposed on a surface of a SAW sensor 400 ofthe test SAW sensor device; and a second SAW sensor device 100(hereinafter referred to as a “control SAW sensor device”). In anexemplary embodiment, a SAW sensor 400 of the control SAW sensor devicedoes not include a receptor disposed a surface thereof.

In an exemplary embodiment of the system, a presence and quantity of thetarget samples is analyzed based on a difference between a signalgenerated from the binding of the target material to the receptor on thesensor surface of the test SAW sensor device and a signal generated fromthe control SAW sensor device not having the receptor.

In yet another alternative exemplary embodiment, a method of controllinga liquid using the SAW sensor device 100 is also provided. Specifically,the method of controlling the liquid includes allowing a liquid in thefirst sample chamber 211 and/or the second sample chamber 212 tohorizontally move (e.g., to move along the x- and/or z-axes of FIG. 3)and to the SAW sensor 400 by a transfer driving force provided from theliquid controller 310 disposed outside, e.g., external to, the main body200 of the SAW sensor device 100.

The transfer driving force may be atmospheric pressure, e.g., airpressure. In an exemplary embodiment, the liquid controller 310 is notin direct contact with the liquid in the main body 200, since it isdisposed outside the main body 200, and instead allows the air to moveinto and out of the main body 200 to drive the liquid therein. Thus,contamination of the liquid controller 310 by the liquid issubstantially reduced and/or is effectively prevented.

Sensing using the SAW sensor device 100 according to exemplaryembodiments may further include stabilizing a signal by installing theSAW sensor device 400 proximate to the oscillator 600 and operating theoscillator 600, setting an oscillation signal to a base line byinjecting a reference solution into the first sample chamber 211 and/orthe second sample chamber 212 and thereafter into the SAW sensor 400,and monitoring the oscillation signal while injecting the target samplein the first sample chamber 211 and/or the second sample chamber 212into the SAW sensor 400.

The monitored signal may be a frequency, a phase or an amplitude, forexample, but alternative exemplary embodiments are not limited thereto.When the target sample moves to the SAW sensor 400 from the first samplechamber 211 and/or the second sample chamber 212, the receptor 405attached to the upper surface of the SAW sensor 400 reacts with a targetmaterial in the target sample, resulting in a wave change in themonitored signal. Thus, the presence, content and type of the targetmaterial in the target sample are detected based on a difference betweena base line and the wave change when a target sample has been injected.

The liquid passing through the SAW sensor 400 then moves to the firstdisposal chamber 220 to be disposed.

In an exemplary embodiment, the method may further include removing airbubbles remaining in a channel, such that the air bubbles are notinjected into the SAW sensor 400 after the liquid moves therethrough.After sensing, the SAW sensor device is washed with a washing solution,and the base signal may be re-measured.

Thus, in a SAW sensor device according to exemplary embodiments, aliquid controller is not disposed in a main body through which a liquidflows, and the liquid is therefore not in contact with the liquidcontroller. Thus, noise due to contamination of the liquid controller,such as contamination of a valve or a pump thereof, for example, issubstantially reduced and/or is effectively minimized In addition, reuseof the liquid controller is possible, and the SAW sensor deviceaccording to an exemplary embodiment therefore provides substantiallyimproved economical and industrial efficiencies.

While exemplary embodiments have been disclosed herein, it will beunderstood that additional alternative exemplary embodiments may bepossible. Such additional alternative exemplary embodiments are not tobe regarded as a departure from the spirit or scope of the generalinventive concept disclosed herein. Rather, the exemplary embodimentsdescribed herein are provided so that this disclosure will be thoroughand complete and will fully convey the general inventive concept tothose skilled in the art.

Thus, it will be understood by those of ordinary skill in the art thatvarious changes in form and details may be made in the exemplaryembodiments described herein without departing from the spirit or scopeof the present invention as defined by the following claims.

1. A surface acoustic wave sensor device comprising: a main bodycomprising: a sample chamber; a surface acoustic wave sensor connectedto the sample chamber; a first disposal chamber connected to the surfaceacoustic wave sensor; and channels connecting the sample chamber, thesurface acoustic wave sensor and the first disposal chamber; and aliquid controller disposed external to the main body, wherein the liquidcontroller controls flow of a sample through the main body.
 2. Thesurface acoustic wave sensor device of claim 1, wherein the liquidcontroller is disposed above the main body.
 3. The surface acoustic wavesensor device of claim 1, further comprising a cover disposed on anupper surface of the main body, wherein the upper surface of the mainbody is disposed opposite a lower surface of the main body, the lowersurface disposed closer to an oscillator than the upper surface, and theliquid controller is disposed on the cover.
 4. The surface acoustic wavesensor device of claim 1, wherein the liquid controller controls theflow of the sample by adjusting at least one of inflow of air to themain body and outflow of air from the main body.
 5. The surface acousticwave sensor device of claim 1, wherein the liquid controller comprisesone or more of valves and a pump.
 6. The surface acoustic wave sensordevice of claim 5, wherein the valves are connected to at least one ofthe sample chamber and the first disposal chamber.
 7. The surfaceacoustic wave sensor device of claim 5, wherein the pump comprises oneof a positive pressure pump and a negative pressure pump.
 8. The surfaceacoustic wave sensor device of claim 5, wherein when the pump is thepositive pressure pump, the pump is disposed at an inlet of the liquidcontroller, and when the pump is the negative pressure pump, the pump isdisposed at an outlet of the liquid controller.
 9. The surface acousticwave sensor device of claim 1, wherein the sample chamber and the firstdisposal chamber include openings formed in surfaces thereof, and theliquid controller is in fluid communication with the main body via theopenings.
 10. The surface acoustic wave sensor device of claim 3,wherein a side of at least one of the sample chamber and the firstdisposal chamber is inclined at an acute angle with respect to animaginary plane aligned substantially perpendicular to a plane definedby the upper surface of the main body.
 11. The surface acoustic wavesensor device of claim 10, wherein the acute angle is from about 1degree to about 60 degrees.
 12. The surface acoustic wave sensor deviceof claim 10, wherein the acute angle is from about 5 degrees to about 30degrees.
 13. The surface acoustic wave sensor device of claim 1, whereinthe sample is a liquid which includes one selected from a groupconsisting of a solution containing a target material, a referencesolution, a washing solution, a buffer solution and any combinationsthereof.
 14. The surface acoustic wave sensor device of claim 3, whereinthe channels comprise a first channel connecting the sample chamber tothe surface acoustic wave sensor, and the sample flows through the firstchannel upward toward the upper surface of the main body from a lowerportion of the sample chamber, and thereafter downward toward an uppersurface of the surface acoustic wave sensor.
 15. The surface acousticwave sensor device of claim 14, wherein the first channel extends upwardaway from the lower portion of the sample chamber toward the uppersurface of the main body and substantially perpendicular to a side ofthe sample chamber facing the surface acoustic wave sensor, andthereafter extends downward away from the upper surface of the main bodytoward the upper surface of the surface acoustic wave sensorsubstantially perpendicular to a plane defined by the upper surface ofthe surface acoustic wave sensor.
 16. The surface acoustic wave sensordevice of claim 14, wherein the channels further comprise a secondchannel connecting the surface acoustic wave sensor to the firstdisposal chamber, and the sample flows through the second channel upwardtoward the upper surface of the main body from the upper surface of thesurface acoustic wave sensor, and thereafter into the first disposalchamber.
 17. The surface acoustic wave sensor device of claim 14,wherein the second channel extends upward away from the upper surface ofthe surface acoustic wave sensor toward the upper surface of the mainbody and substantially perpendicular to a plane defined by the uppersurface of the surface acoustic wave sensor, and thereafter extendssubstantially parallel to the plane defined by the upper surface of thesurface acoustic wave sensor toward the first disposal chamber toconnect thereto.
 18. The surface acoustic wave sensor device of claim 1,further comprising a second disposal chamber connected between thesample chamber and the surface acoustic wave sensor.
 19. The surfaceacoustic wave sensor device of claim 18, wherein the second disposalchamber includes an opening formed therein and through which the liquidcontroller is fluidly connected to the main body.
 20. A surface acousticwave sensor system comprising: a first surface acoustic wave sensordevice; and a second surface acoustic wave sensor device, wherein eachof the first surface acoustic wave sensor device and the second surfaceacoustic wave sensor device comprises: a main body comprising: a samplechamber; a surface acoustic wave sensor connected to the sample chamber;a first disposal chamber connected to the surface acoustic wave sensor;and channels connecting the sample chamber, the surface acoustic wavesensor and the first disposal chamber; and a liquid controller disposedexternal to the main body, wherein the liquid controller controls flowof a sample through the main body, a receptor is disposed on a surfaceof the surface acoustic wave sensor of the first surface acoustic wavesensor device, and a receptor is not disposed on a surface of thesurface acoustic wave sensor of the second surface acoustic wave sensordevice. 21.-25. (canceled)